<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        let a = 12;
        let b = 10;
        let c = 5;          // a = 13 d = 12
        let d = a++;        //  c = 5
        console.log(d);			// d = 13
        let e = ++b;
        console.log(e);        //  e = 11
        let f = c + d++;
        console.log(f);     //   f = 18
        let g = c + ++d;
        console.log(g);      //   g = 19
        // 算出d, e, f, g的值。
       
    </script>
</body>

</html>